Process for converting sodium sulfate to sodium sulfid



R. J. ANDERSON.

PROCESS FOR CONVERT'lNG SODIUM SULFATE TO SODIUM SULFID.

APPLICATION FILED SEPT- 30| I920.

Patented Nov. 22, 1921.,

ROBE JAMES ANDEON, 015 EL CONSERVATION CO.,

JPASO, 5.1 ASSIGNOR TO INTERNATIONAL FUEL OF PHOENIX, ARIZONA, A. CORPORATION OF ARIZONA;

PROCESS FOR CONVTING' SODIUM SULFATE TO SODIUM SULFID.

Specification of Letters Patent.

Patented Nov. 22, rear.

Original application filed March 6, 1.919, Serial No. 281,037. Divided and this application filed September 30, 1920. Serial No. 4413,752.

To all whom it may concern:

Be it known that 1, ROBERT JAMEs ANDER- SON, a citizen of the United States, residing at El Paso, in the county of El Paso and State of Texas, have invented certain new and useful Improvements in Processes for such as the manufacture of Portland cement,

manufacture of glass, the conversion of sodium sulfate into sodium sulfid and the conversion of sodium sulfate into sodium oxid. The process finds particular usefulness in the conversion of sodium sulfate into either the sulfid or the oxid and the examples of the processhereinafter set forth and which are disclosed in the accompanying drawings pertain particularly thereto. I do not, however, limit the invention to practice of the process only in the converslon of sodium sulfate.

In the practice of the process for the manufacture of sodium sulfid or sodium oxid, there is employed an inclined tubular rotary furnace or kiln wherein the rotation of the furnace or kiln causes the sodium compound to continuously rise up the upwardly turning interior wall of the kiln or furnace and to fall vertically, While advancing steadily in the direction of the length of the furnace or kiln.

In the conversion of sodium sulfate to sodium sulfid, the chemical reactions and conversions are efiected at a temperature of about 960 0., at which temperature the product becomes soft and pasty and in condition. for conversion which can only be accomplished in the presence of excess carbon in the gases and not in an oxidizing temperature. If the temperature exceeds the critical point, the product becomes rapidly fused, liquefies and adheres to the sides of the furnace or kiln, forming sodium silicate by union with the furnace lining.

My process for the conversion of heavy chemicals, for instance sodium sulfate into sodium sulfid, contemplates the complete and accurate control of both the furnace temperatures and the condition of the gases.

Primary and secondary combustion processes are carried on in separate combustion chambers. The C0 :gases from the secondary process are discharged into the end of the rotary furnace or kiln in such manner as to direct the flames of the reducing gases in close contact along the line and top of the advancing charge of the sodium sulfate at a time when the material has reached the temperature requisite for conversion into sodium sulfid. The conversion from sodium sulfate to sodium sulfid is almost instantaneous when contact is had with the carbon in the gases at proper temperatures. The constant discharge of the converted material makes the conversion process practically automatic and continuous.

The primary combustion process produces CO gases which are utilized to heat the Walls of the rotary furnace or kiln and, by radiation from these walls furnishing the interior of the rotary furnace or kiln with a flame of neutral heated gases insuringaccurate, complete and definlte control of th prolduct and effecting economy in the use 0 fue As a result of the specified application of the CO and CO, gases derived, respectively, from the secondary and primary combustion processes, there is a constant discharge of sodium sulfid from the delivery end of the rotary furnace or kiln and, conse- .quently, a direct,-automatic and continuous process of conversion of sodium sulfate into sodium sulfid is obtained. This obviates two troublesome and expensive steps formerly required, namely, leaching of the roasted product, decanting and settling the liquors; and, the second step of evaporation of the liquid solutions down to the finished commercial product. I

In the practice of my process for the conversion of sodium sulfate into sodium oxid,

the secondary combustion process providing gases, is not used. The CO gases from the primary combustion chamber are so regulated that the complete combustion of the fuel for the purpose of liberating substantially all of the heat units is carried on and so regulated that an excess of oxygen is present in the furnace or kiln. In the production of sodium oxid, lime is added and the following reactions occur; the sulfur in the sodium sulfate leaves the sodium and combines with the lime for which it has a greater affinity and forms calcium sulfid,

the excess oxygen furnished the CO gases belng present in sufficient quantities to unite with the sodium to form sodium oxid.

paratus used for that purpose may be that which is set forth and claimed in my Patent No. 1,362,212, December 14, 1920, for combustion apparatus.

. -F or practising the present process in the conversion of Sodium sulfate to sodium oxid,

the secondary combustion process of my ap- "plica'tion Serial No. 281,037, and the apparatus of my Patent No. 1,362,212 for carrying on a secondary combustion may be employed.

The secondary and primary combustion processes being tully'set forth in my said application Serial No. 281,037 and the apparatus in Patent No. 1,382,212, further e-Xpla-- nation thereof, except as hereinafter explained, is unnecessary.

In the accompanying drawing,

Figure 1 isa side elevation of a rotary furm ce or kiln equipped with primary and secondary combustion chambers, constituting an apparatus adapted for practising my process;

Fig. 2 is a vertical section through the primary and secondary combustion chambers on the line 22 of Fig. 1; a

Fig. 3 is a section onthe line 3-3 of Fig.1;

Fig. 4 is a horizontal section on the line H of Fig. 2, showing the relative arrangemerit oi. the fuel and air jets or sprays and their interplay in effecting combustion;

-Fig'. 5 is a detail section showing one oi' the fuel supplying nozzles; and

Fig. 6 is a similar View of one of the refractory air distributing tubes.

The apparatus illustrated in the drawings is particularly adapted for the practice of the process in converting sodium sulfate to sodium sulfid or sodium sulfate to sodium oxid. The rotary kiln or furnace 78 is of a well-known form and receives the material in any suitable manner as, for instance, through a feed chute or hopper 79. The chimney for the furnace is shown at 80. The primary combustion chamber appears at 81 and secondary combustion chamber is shown at 82. The fuel is jetted or sprayed into the combustion chamber 81 by nozzles or other suitable means 83, under suitable valve control 84. A form of nozzle adapted for this purpose is shown in Fig. 5, the same being suitably set in the wall of the combustion chamber. The air is jetted or sprayed from air distributers 15 in the chamber 81 under suitable valve control 85. The air distributers are in the form of refractory nozzles or tubes having perforations 17 and are suitably set in the wall of the chamber, as shown in Fig. 6.

The play of the finely divided fuel delivered within the combustion chamber 81 and the air jets issuing from the distributers 15 is such that the fuel, for instance, liquid h' drocarbon, is jetted or sprayed in finely ivided form into and through the numerous air jets which issue from the perforations 17. The cross play of the finely divided fuel jets and the direction of play of the air jets is at an angle, preferably nearly a right angle, to the direction of final travel of the gases derived from combustion as they flow toward their point of utilization in therotaryv kiln or iurnace 78.

' As fully explained in my applications heretofore specified, the cross play and interaction I of the fuel and oxygen derived from the air jets results in not only the exterior of the body or mass of flame derived from combustion being converted into C(), in the chamber 81, but also, the entire inte- -rior of the mass or body of flame is thus converted. The staggered relationship of the rows of air distributers 15 to the fuel distributing nozzles 83 insures that the air issuin from the perforations 17 of each air distributer 15 will form a complete admixture with the jetted or sprayed fuel from the nozzles.

In the combustion chamber 82 the fuel is introduced by nozzles 86 under valve control 87, said nozzles being similar to the showing of Fig. 5. The air is introduced at 88 under valve control 89, the purpose being to provide excess carbon in the chamber 82 to carry out the secondary combustion process in said chamber 82 and to produce CO gas. The direction or" play of the air and fuel in relation to each other and to the path of final travel of the CU gas evolved from combustion in the chamber 82 is the same as in the chamber 81.

A collar or hood 90 surrounds the delivery end of the furnace or kiln 7 8 and has a suitable outlet 91 for the sodium sulfid. A flue or outlet 92 directs the CO, gases from the combustion chamber 81 into the delivery end tit) I t eme"! of the rotary furnace 78 to the point designated CO Fi 93 directs the C gases from the combustion chamber 82 into therotary furnace or kiln 78 in the general region designated CO, Figs. 1- and 3.

In the production of sodium sulfid from sodium sulfate the chemical reactions occur at about 960 C., at which temperature the product becomes soft and pasty, permitting conversion. This conversion can only be accomplished in the presence of excess carbon in the gases and not in an oxidizing or neutral atmosphere. Care should be taken that the temperatures do not rise above the point indicated as the roduct would rapidly fuse and adhere to the furnace lining, forming sodium silicate, if the temperatures 0 up.

In practising my process the C gases from the secondary chamber 82 discharge in close contact along the line and on top of the advancing charge of material as 1ndicated at C0. This occurs when the material has reached the temperature necessary to effect conversion, the revolutions of the furnace 78 constantly turning the material over and exposingall portions of the mass to the action of the reducing gases. The con-. version of the product from sodium sulfate to sodium sulfid is almost instantaneous when contact is had with the carbonin the gases at proper temperatures. The constant discharge of the converted material makes the conversion process practically automatic and continuous. 7 a 1 The combustion process practised in the upper or main chamber 81 furnishes C0 1 gas to the interior of the rotary furnace 78 as indicated C0 affording the heat re- MT quired for the radiation from the walls of the furnace 78. The automatic and con- I of sodium sulfate to sodium sulfid, consisting.

tinuous process thus carried on, results in a high class product of sodium sulfid and 0bviates two troublesome and expensive ste s heretofore necessary, towit: leaching of the roasted product, decanting and settli the liquors; and secondly, evaporation 3% the liquid solutions of the finished commercial product. While I have illustrated certain applications of my primary and secondary combustion processes, this is done by way of 1 and 3. A flue or outlet.

illustration of the scope of the invention and not in limitation thereof, as many other applications of the process may be had, among which are the conversion of sodium sulfate into sodium oxid where lime is added, and the manufacture of 'Portland cement, in kilns such as shown in Figs. 1 and 3, and in the manufacture of glass in glass furnaces.

In the production of sodium Hoxid from sodium sulfate, the secondary, or C0 combustion, is not used. The gases from the (30 chamber are so regulated that the complete combustion of the fuel for the purpose of liberating substantiall all the heat units is carried on and so reg-u ated that an excess of oxygen is present in the kiln. In this case, lime is added and the following reactions occur: the sulfur in the sodium sulfate leaves the sodium and combines with the lime for it has a greater affinity and forms calcium sulfid, the excess oxygen furnished the CO gases being present in suficient quantities to unite with the sodium to form sodium oxid. a

My processes enable perfect regulation tr temperature at which conversion may occur.

3. A' process for the continuous conversion in continuous shifting and advancing the sodiumsulfate in a rotary furnace or kiln while maintaining a suitable temperature for conversion of the materialinto sodi sulfid by C0,, gases directly introduced into the kiln, and subjecting the shifting and advancing material to the direct action of CU ases. I g In testimon whereof I it my siature.

RUB RT. JAMES ANDERUN.

Mill) 

